Video Transmission System

This application claims the priority benefits of Japanese application no. 2025-020773, filed on February 12, 2025. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

The disclosure relates to a video transmission system that transmits video data between an encoder and a decoder.

Recently, video transmission systems that transmit video captured by a camera from one communication device to another communication device via a communication line as video data converted to serial data have been used in vehicles and the like (Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2024-093153). In conventional video transmission systems, typically, one communication device includes an encoder for serial data conversion, and the another communication device includes a decoder for parallel data conversion.

In conventional video transmission systems, since video data transmission is unidirectional communication from one communication device to another communication device, back channel communication is configured to enable data transmission from the another communication device to the one communication device for data communication other than video data. Back channel communication enables, for example, changing the communication mode of video data or changing the shooting mode of the camera from another communication device to the one communication device.

However, this presented a problem in that in a state where communication establishment between communication devices is not correctly performed for back channel communication, malfunction or failure may be caused during data transmission in back channel communication.

Therefore, an object of the disclosure is to provide a video transmission system that is capable of reliably performing communication establishment between communication devices for back channel communication.

The video data transmission system of the disclosure is a video transmission system for transmitting video data from an encoder to a decoder via a first communication line, in which the encoder includes: a first transmission part that transmits a specific signal for communication establishment to the decoder via the first communication line during a blanking period of the video data; and a determination part that determines communication establishment of back channel communication in a case of receiving a command signal indicating communication establishment from the decoder via a second communication line after transmission of the specific signal. The decoder includes a judgment part that judges whether or not a signal received from the encoder during the blanking period is the specific signal; and a second transmission part that transmits the command signal to the encoder via the second communication line in a case of the received signal being the specific signal, and the encoder and the decoder execute the back channel communication via the second communication line after determination of the communication establishment of the back channel communication.

The video data transmission system of the disclosure is a video transmission system for transmitting video data from an encoder to a decoder via a first communication line. The video transmission system includes a control unit that is connected to the decoder, and that issues a communication establishment request to the decoder in response to receiving a specific signal detection notification. The encoder includes a first transmission part that transmits a specific signal for communication establishment to the decoder via the first communication line during a blanking period of the video data; and a determination part that determines communication establishment of back channel communication in a case of receiving a command signal indicating communication establishment from the decoder via a second communication line after transmission of the specific signal. The decoder includes a judgment part that judges whether or not a signal received from the encoder during the blanking period is the specific signal; a notification part that supplies the specific signal detection notification to the control unit in a case of the received signal being the specific signal; and a second transmission part that transmits the command signal to the encoder via the second communication line according to the communication establishment request, and the encoder and the decoder execute the back channel communication via the second communication line after determination of the communication establishment of the back channel communication.

Hereinafter, the video transmission system of the disclosure will be described in detail with reference to the drawings.

1 FIG. 11 12 13 11 12 41 42 12 13 43 shows the video transmission system of the disclosure. This video transmission system includes, as communication devices, an encoder, a decoder, and an MCU (Microcontroller Unit). The encoderand the decoderare connected to each other by communication linesand. The decoderand a MCUare connected to each other by a data line.

11 21 22 23 21 22 21 12 22 31 32 33 34 41 31 32 42 33 34 41 42 12 11 The encoderincludes a video source, a transmission and reception part, and a state management part. The video sourceis, for example, a camera and generates a video signal that is parallel data. The transmission and reception partis connected to the video sourceand is a part that performs data communication including video data with the decoder. The transmission and reception partincludes a video data transmission part, a specific signal transmission part, a command signal reception part, and an ACK (ACKnowledgement) signal transmission part. The communication lineis connected to the video data transmission partand the specific signal transmission part, and the communication lineis connected to the command signal reception partand the ACK signal transmission part. The communication lineis a first communication line and is a unidirectional communication line. The communication lineis a second communication line for back channel communication and is a communication line capable of bidirectional communication. Back channel communication is communication performed from the decodertoward the encoder.

31 21 12 41 32 23 12 41 33 12 42 13 34 23 12 42 The video data transmission partconverts the video signal supplied from the video sourceinto video data that is serial data, and transmits the video data to the decodervia the communication line. The specific signal transmission partinserts the specific signal supplied from the state management partinto a blanking period of the video data and transmits it to the decodervia the communication line. The blanking period is other than the video portion of the video data and the vertical and horizontal sync signal portions, and is a period that is not displayed on the screen of the display. The specific signal is a signal that instructs the start of back channel communication. The command signal reception partreceives the command signal transmitted from the decodervia the communication line. The command signal is a signal generated by the MCU. The ACK signal transmission parttransmits the ACK signal supplied from the state management partto the decodervia the communication line.

23 22 23 51 52 53 The state management partis a part that manages the operating state of the transmission and reception part. The state management partincludes a specific signal generation part, a command signal judgment part, and an ACK signal generation part.

51 32 51 52 33 53 52 53 34 The specific signal generation partgenerates a specific signal and supplies the specific signal to the specific signal transmission part. The generation of the specific signal by the specific signal generation partmay be performed, for example, according to an input operation from the outside, or may be performed automatically at predetermined time intervals. The specific signal is composed of a predetermined code sequence, for example, ABCD. The command signal judgment partaccepts the command signal received by the command signal reception partand judges whether or not the command signal is a predetermined command signal. The ACK signal generation partgenerates an ACK signal according to the judgement result by the command signal judgment part. That is, the ACK signal is generated in the case where it is judged that the received command signal is a predetermined command signal. The ACK signal generation partsupplies the generated ACK signal to the ACK signal transmission part.

12 61 62 63 61 71 72 73 74 41 71 72 42 73 74 The decoderincludes a transmission and reception part, a state management part, and a video output part. The transmission and reception partincludes a video data reception part, a specific signal reception part, a command signal transmission part, and an ACK signal reception part. The communication lineis connected to the video data reception partand the specific signal reception part, and the communication lineis connected to the command signal transmission partand the ACK signal reception part.

71 11 41 72 11 41 73 62 11 42 74 11 42 The video data reception partreceives the video data transmitted from the encodervia the communication line. The specific signal reception partreceives the specific signal transmitted from the encodervia the communication line. The command signal transmission parttransmits the command signal supplied from the state management partto the encodervia the communication line. The ACK signal reception partreceives the ACK signal transmitted from the encodervia the communication line.

62 61 62 81 82 83 The state management partis a part that manages the operating state of the transmission and reception part. The state management partincludes a specific signal judgment part, a command signal generation part, and a communication establishment confirmation part.

81 72 81 13 43 82 13 43 13 42 11 12 82 73 83 74 11 12 42 The specific signal judgment partaccepts the specific signal received by the specific signal reception partand judges whether or not the specific signal indicates a predetermined code sequence. The judgement result of the specific signal judgment partis supplied to the MCUvia the data line. The command signal generation partis connected to the MCUvia the data lineand generates a command signal indicating predetermined communication establishment according to a communication establishment request from the MCU. The communication establishment here is establishment of a connection for back channel communication using the communication linebetween the encoderand the decoder. The command signal generation partsupplies the generated command signal to the command signal transmission part. The communication establishment confirmation partaccepts the ACK signal received by the ACK signal reception partand confirms communication establishment between the encoderand the decodervia the communication lineaccording to the ACK signal.

63 61 71 63 63 The video output partis connected to the transmission and reception part, and the video data received by the video data reception partis supplied to the video output part. For example, the video output partis a display that displays the video indicated by the supplied video data or a storage device that stores the video data.

13 12 43 13 43 81 13 82 43 13 83 43 83 The MCUis a host device and is connected to the decodervia the data lineas described above. The MCUis enabled to receive, via the data line, a judgement result indicating that the specific signal indicates a predetermined code sequence from the specific signal judgment partas a specific signal detection notification. In the case of receiving the specific signal detection notification, the MCUsupplies a communication establishment request to the command signal generation partvia the data line. The communication establishment request may be generated only in the case of requiring back channel communication. Moreover, the MCUreceives a communication establishment notification from the communication establishment confirmation partvia the data linein the case where the communication establishment of back channel communication is confirmed by the communication establishment confirmation part.

42 42 22 11 61 12 Back channel communication is communication via the communication lineas described above, and in this embodiment is serial communication using an I2C (Inter-Integrated Circuit) communication method. In I2C communication, the communication lineincludes a signal line for data and a signal line for clock. Moreover, although not illustrated, each of the transmission and reception partof the encoderand the transmission and reception partof the decoderincludes a transmission and reception part for data communication using the I2C communication method.

2 FIG. Next, the communication establishment operation of back channel communication in the video transmission system having such configuration will be described using the sequence diagram of.

11 51 11 32 12 41 12 In the encoder, for example, the specific signal generation partgenerates a specific signal according to an instruction from outside (step S), and the specific signal is transmitted from the specific signal transmission partto the decodervia the communication line(step S). The specific signal is superimposed on the blanking period of the video data during transmission.

12 72 41 13 81 81 14 13 43 15 In the decoder, the specific signal reception partreceives by extracting a signal other than video data from the blanking period of the video data that arrived via the communication line(step S). The received signal is supplied to the specific signal judgment part. In the specific signal judgment part, it is judged whether or not the received signal indicates a specific signal including a predetermined code sequence (step S). In the case of the received signal indicating a specific signal of a predetermined code sequence, the judgement result is supplied to the MCUas a specific signal detection notification via the data line(step S).

13 16 82 43 17 In the MCU, in response to receiving the specific signal detection notification (step S), a communication establishment request is generated, and the communication establishment request is supplied to the command signal generation partvia the data line(step S).

82 13 18 73 19 73 11 42 20 42 In the command signal generation part, in response to receiving the communication establishment request from the MCU(step S), a command signal indicating communication establishment is generated according to the communication establishment request, and the command signal is supplied to the command signal transmission part(step S). In the command signal transmission part, the command signal is transmitted to the encodervia the communication line(step S). The transmission of the command signal via the communication linemay be performed during the blanking period of the video data.

11 20 33 21 52 52 22 53 23 34 12 42 34 24 In the encoder, the command signal transmitted in step Sis received by the command signal reception part(step S). The received command signal is supplied to the command signal judgment part, and the command signal judgment partjudges whether or not it is a predetermined command signal (step S). In the case of the received command signal being a predetermined command signal, an ACK signal is generated by the ACK signal generation part(step S). The generated ACK signal is supplied to the ACK signal transmission part, and is transmitted to the decodervia the communication lineby the ACK signal transmission part(step S).

12 24 74 25 83 83 26 26 13 43 27 In the decoder, the ACK signal transmitted in step Sis received by the ACK signal reception part(step S). The received ACK signal is supplied to the communication establishment confirmation part, and the communication establishment of back channel communication is confirmed by the communication establishment confirmation partin response to the reception of the ACK signal (step S). In response to the communication establishment being confirmed in step S, a communication establishment notification is transmitted to the MCUvia the data line(step S).

11 12 12 11 28 29 13 12 11 11 12 13 11 11 11 I2 I2 11 Moreover, in response to the communication establishment of back channel communication being confirmed, in addition to the transmission of video data from the encoderto the decoder, back channel communication from the decoderto the encoderis possible (step S). In response to receiving the communication establishment notification (step S), the MCUmay control transmission data from the decoderto the encoderin a state where back channel communication is possible between the encoderand the decoder. Moreover, the MCUmay instruct transmission and reception of data for performing operation settings of the encoderand devices connected thereto, such as write/read of registers in the encoder, control of SPI-flash memory connected to the encoder,C write/read to other devices connected to anC bus connected to the encoder, and the like.

32 11 1 2 3 4 3 FIG.A As described above, the predetermined code sequence of the specific signal is transmitted by the specific signal transmission partof the encoderso as to be arranged in the blanking period of the video data. The predetermined code sequence of the specific signal is arranged in the blanking period of any or predetermined single line of the video data, or is distributed and arranged in the blanking periods of predetermined multiple lines in one frame of video data. For example, in the case of the code sequence “ABCD” , as shown in, distributed arrangement is performed with “A” arranged in line numberof the video data, “B” arranged in line number, “C” arranged in line number, and “D” arranged in line number. Moreover, the code sequence “ABCD” may be sequentially arranged in any one or more arbitrary lines in one frame of the video data.

12 72 81 81 13 82 1234 73 3 FIG.A 3 FIG.B 3 FIG.B In the decoder, in the case of the signal received by the specific signal reception partbeing “ABCD” of, in the case of “ABCD” being present in the specific signal judgment partas an expected value of reception as shown inas a predetermined code sequence, the specific signal judgment partperforms match judgement and generates a specific signal detection notification. Thereby, the MCUgenerates a communication establishment request, and the command signal generation partgenerates a command signal including the fixed value “” as shown in, and the command signal is transmitted from the command signal transmission part.

11 1234 52 42 3 FIG.C In the encoder, as shown in, in the case of a command signal including the fixed value “” being received, the command signal judgment partjudges that it is a predetermined command signal, and communication establishment is confirmed. As a result, back channel communication becomes possible using the communication line.

12 72 81 4 FIG.A 4 FIG.B 4 FIG.C On the other hand, in the decoder, even in the case of the signal received by the specific signal reception partbeing “ABCD” of, in response to “ABCD” not being present in the specific signal judgment partas shown inas an expected value of reception as a predetermined code sequence, since no specific signal detection notification is generated, no command signal is generated, and as shown in, communication establishment is not performed.

5 FIG.A 5 FIG.B 5 FIG.C 11 81 81 As shown in, in the case of the specific signal not being inserted in the blanking period of the video data in the encoder, even though “ABCD” is present in the specific signal judgment partas an expected value of reception as a predetermined code sequence as shown in, the specific signal judgment partcannot recognize the specific signal by match judgement. In this case as well, since no specific signal detection notification is generated, no command signal is generated, and as shown in, communication establishment is not performed.

11 12 In the case of communication establishment not being performed in this manner, back channel communication is not executed, and transmission of video data from the encodertoward the decoderis continued.

According to the video transmission system of the disclosure, communication establishment in back channel communication can be reliably executed, and data transmission by back channel communication can be started after communication establishment confirmation, so malfunctions and failures can be prevented during back channel communication.

13 13 12 11 13 11 Moreover, the video transmission system of this embodiment includes the MCU, but the MCUis not essential in the video transmission system. The decodermay transmit a command signal to the encoderwithout transmitting a specific signal detection notification to the MCUin the case of performing reception and judgement of the specific signal transmitted from the encoder.

The disclosure is not limited to the forms of the embodiments described above, and various improvements and design changes are possible within a range that does not depart from the gist of the disclosure.

The following configurations are disclosed in this specification.

A video transmission system for transmitting video data from an encoder to a decoder via a first communication line, in which the encoder includes a first transmission part that transmits a specific signal for communication establishment to the decoder via the first communication line during a blanking period of the video data; and a determination part that determines communication establishment of back channel communication in a case of receiving a command signal indicating communication establishment from the decoder via a second communication line after transmission of the specific signal, and the decoder includes a judgment part that judges whether or not a signal received from the encoder during the blanking period is the specific signal; and a second transmission part that transmits the command signal to the encoder via the second communication line in a case of the received signal being the specific signal, and the encoder and the decoder execute the back channel communication via the second communication line after determination of the communication establishment of the back channel communication.

The video transmission system according to configuration 1, in which the specific signal includes a predetermined code sequence.

, The video transmission system according to configuration 2in which the code sequence is distributed and arranged in a plurality of lines in one frame of the video data.

The video transmission system according to configuration 1, in which bidirectional communication is possible on the second communication line.

The video transmission system according to configuration 1, in which data is transmitted from the decoder to the encoder via the second communication line during execution of the back channel communication.

The video transmission system according to any one of configurations 1 to 5, in which the second communication line is a communication line for Inter-Integrated Circuit communication.

The video transmission system according to any one of configurations 1 to 5, in which the second transmission part transmits the command signal during the blanking period.

A video transmission system for transmitting video data from an encoder to a decoder via a first communication line, the system including: a control unit that is connected to the decoder, and that issues a communication establishment request to the decoder in response to receiving a specific signal detection notification. The encoder includes: a first transmission part that transmits a specific signal for communication establishment to the decoder via the first communication line during a blanking period of the video data; and a determination part that determines communication establishment of back channel communication in a case of receiving a command signal indicating communication establishment from the decoder via a second communication line after transmission of the specific signal. The decoder includes: a judgment part that judges whether or not a signal received from the encoder during the blanking period is the specific signal; a notification part that supplies the specific signal detection notification to the control unit in a case of the received signal being the specific signal; and a second transmission part that transmits the command signal to the encoder via the second communication line according to the communication establishment request, and the encoder and the decoder execute the back channel communication via the second communication line after determination of the communication establishment of the back channel communication.